The present invention is directed to overcoming difficulties encountered with various prior art assemblies for gasketing appliance doors, particularly doors of self-cleaning electric ovens.
In such ovens, it is common to mount a flexible glass fiber gasket to the oven door or around the face of the oven to substantially seal the space existing between the door and the face of the oven.
In one prior construction, a resilient, flexible knitted wire mesh tube was inserted into a larger diameter, braided, glass-fiber tube to form a flexible gasket subassembly. A sleeve was formed in one side of the glass fiber tube by sewing together an excess portion of the glass fiber tube along the length of that tube. In this way, the knitted, wire mesh tube was relatively closely held in one portion of the braided glass fiber tube on one side of the stitching and the sleeve was formed by the remainder of the glass fiber tube on the other side of the stitching. The sleeve was thereafter threaded onto an elongated steel member forming a substantially rigid frame to form the gasket assembly.
In one configuration, the ends of the flexible subassembly were secured on the frame by butting or telescoping the ends together and stapling them. In another configuration, the flexible subassembly extended substantially but not completely around the metal frame. Ends of the flexible subassembly were secured to the frame by metal hooks. An end of each hook was inserted through the braided glass fiber tube in the region of the stitching and an opposing end of the hook welded to the metal frame.
The metal frame, which was rectangular in shape, held the flexible subassembly in an identical rectangular shape. The sleeve of the braided tube and the metal frame within formed a tail extending from a remaining, essentially cylindrical and deformable portion of the assembly. The tail was inserted between panels of an oven door or panels of the body of the oven facing the door, to secure the assembly in position.
There were certain drawbacks associated with this construction. These drawbacks related to both the method of fabrication and the gasket assembly resulting from that method.
First, the methods employed for securing the gasket assembly on the frame were not easy to perform. The hooks were particularly burdensome as they had to be initially fabricated and then secured to the metal frame but only after the flexible subassembly had been threaded onto the metal frame. Moreover, when the hooks were eliminated and the ends of the flexible assembly were stapled together, there was the possibility of the braiding unraveling at the staple(s), resulting in a loss of tension in the subassembly and possibly a complete separation of the ends of the braiding, and the undesired movement of the subassembly around the frame.
Second, tensioning the braided glass fiber jacket sufficiently to cause it to lie smoothly along straight portions of the frame while not bunching up along the inside of curves of the frame was difficult, if not impossible. When greater tension was applied to the braided tube to smooth it at the curves, the braid had a tendency to flatten into the curve to relieve tension and further to narrow in diameter along straight portions of the assembly. This often led to problems with sealing between the oven door and face of the oven apparently due to uneven diameter of the braided glass tube along the frame.
Yet another gasket assembly has been used which consists of two braided glass fiber tubes positioned adjoining one another and sewn to one another along their lengths. An enlarged sleeve of one of the two glass fiber tubes contained a resilient, flexible knitted metal wire tube which formed the deformable portion of the gasket assembly. In a pocket formed in the second glass fiber tube, on the same side of the stitching as the knitted metal wire tube, a resilient metal wire frame member was inserted. This gasket assembly was installed along flange, the flange being positioned between the two braided glass fiber tubes. In that way, the glass fiber tube with flexible, deformable knit wire inner tube would be exposed on an "outer" surface of the flange while the second braided glass tube and metal wire frame member could be concealed on a "hidden" side of the flange.
This particular construction with the knit metal wire tube and resilient metal frame member on the same side of the stitching resulted in substantially uniform bending of the two braided glass fiber tubes at corners of the supporting flange. The drawback of this construction is that it is essentially usable only with the provision of such a supporting flange and was not useful with other types of oven and oven door construction, particularly those having inside as opposed to outside curves.